CA2180181A1 - Filtration and combustion process for carbon particulate matter from an internal combustion engine - Google Patents

Abstract

The object of the invention is a filtration and combustion process for carbon particulate matter from an internal combustion engine. The process is characterized by the following steps: a rare earth or rare earth mixture derivative is introduced into the fuel at a concentration of 10 ppm to 500 ppm (by weight), and preferably of 20 ppm to 200 ppm; the soot produced by the internal combustion engine is collected on a filter, the temperature of the gases entering the filter being selected in the range of 100 ~C to 350 ~C; the soot is allowed to build up until a significant fraction or rate of incoming soot is balanced by the combustion of soot in the soot cake on the filter, and no regeneration is effected as long as the head loss caused by the soot does not exceed a preselected value and is not higher than 400 millibars. This invention is useful for organic synthesis.

Description

WO 95/18198

2 1 8 3 1 8 I PCT / FR94 / 01560 A FILTRATION AND COMBUSTION PROCESS
OF COMBUSTION ENGINE ISS ~ IFS CARBON MATERIALS
INTERNAL.
.

The ~ rese "te invention relates to a process ~ d ~ filtration and combustion of carl onées materials from internal corr ~ bustion engines. The invention coocer "e more particular", 6nt the regulation of the pressure drop in the filters by the accumulation of soot in the filters.
When filling up fuels in internal filling engines and not ~ "ment when that of diesel in the diesel engine, forms ", ~ liers carLG" ées, hereinafter Jgno """ées ~ soot ~, which are r ~ rvt ~ es harmful both for the health of, -, ~"", ifères higher than for env..u, , nel, -e, lt.
These soot are particular ~, ne, lt abund ~, your in the case of diesel engines and con ~ tihJent a handicap for this type of engine. Most solutions envisaged ~ ées consi ~ as chan ~ er engine speed or its ~ ar ~ .. ~ s for, .tiGnnel "e, lt face another constraint, that of not lying 20 I'é ", ission of carl monoxide, ol, e eVou of gæ deemed toxic and mutagenic such as nitrogen oxides.

Given what ~, recedes, the most pe technique, f ~ r ", a, lte seems to be t ~ 1; Gn in the flash pot, a ~. ~, e ", e, lt of a filter capable of stopping all or 25 at least the most there. ~ I part of the soot f ~ r, .. ées by the comblJstion of various fuels.

We thus succeeded in making filters, not ~. "" E, lt in cordierite. who, ~ Jem ~ she ~ lt's reduce the soot emissions by at least 85% by mass.
The ~, ol l ~ l "e to solve lies in the accumulation of this soot in the filters which initially causes a ~ ", entatiG-- of loss of char ~ e and, in a delJ ~ th time, a beginning of obturation which leads to a loss of ren.Jen, 6 "~ of the internal combustion engine.

Many techniques have been tried for burning this soot. So we have , uropose to cause the con ~ b ~ stion of these soot in an inter ", itle,) either by electric heating either by heating by means of a combustih'e 21 ~ 01 ~ 1 fossil igniter. We also considered the possibility ~ ~ to draw heat necess ~; ~ e the ignition of this soot in the engine itself by a skillful y6sli ~ n flow of gas to heat the soot accumulated in the filter and ipso facto to cause their ir, ll ~ "", dlio "(len" .élal.lre of the order of 500-5 600C).

We have ~ alement, ur ~ dared to i-lt ~ uire catalyst precursors J'i, Illa, n, o ~ tion in Jitf ~ rents fuels, so ~ h ~ isser the temperature of i "tl ~, ~ r" dliGn of soot. These techniques, notam ", 6n ~ that of 10 conlbi,) aison de auy ", entaliGn de la te"", ~ soot reading using a circuit ~ dart ~ et ~ si ~ oire des ~ d'écl, ap ~ .e ", ent with the ~ d ~ Ji1; ol, precursors of oxidation catalyst, have at least partially resolved the problem.

15 To ~ however, on the one hand the te ", ~ rdture il ~ tl ~ lll" dtiGn soot remains relatively high (of the order of 500C) and on the other hand intermittent corrbustions and brutal risk of o ~ n "ering an allg.aliGn if ~ .if, ~ linked to the filter and its because ~ c ~ s of lil ~ iGn, either by weaving due to thermal shock, or even by tusion.
20 This alléraliG,) of the filters can pr ~, ~ JI e the form of a loss of cal ~ ci ~ to remember a fault for a hundred years of soot, while the initial percentage is sometimes estimated insufficient.
This is why one of the aims of the present invention is to rotate a ~ uroc ~ die corrosion of the soot which is as continuous as possible.
25 Another object of the present invention is to provide a ~ ,, oc ~ Jé de comblJstion soot which doesn’t ~ ho ~ go to i., ll ~ ... oa ~ iGns brutal, violent and Soud ~ es leading to endG - .., -, a ~ er the filter. To reach such a r ~ suh ~ t it is advisable to avoid that during b phase .J'i., Tl ~ .., n ~ n, in no place of the filter temperature ~ ture reaches 1000C, av ~ lt ~ eus ~ --e-lt 900C, from ~, ref ~ rence 30 700C.
Measuring bs ter is difficult. ", Local erections, so it has been established that these ~ ar..ières constraints cGr-espol, due to te "" ~ r ~ gas tures --a, ~ i nales, to the filter output, at most about 600C (~ about ~ if ~ here indicates that zeros, which are here zeros of l-osit; we, are not chfflres signifiG ~ tifs), de ~ .référ ~, .ce à
35 500 C approximately.
Another object of the present invention is to ~ oumir a method of ~ dliGn and comblJstion soot, which improves the pr ~ pG li ~ n retained soot on the ~ iltres then later br ~ lée.

WO95 / 18198 ~ 1 8 to 1 8 I PCT / FR94101560 These goals, and others which will be arduated later, are achieved by means of a procgJ ~ de traitel "6nt de soot Cont ~ n ~ lt one or more rare earths, procg.l ~
in which one puts in conta ~ A bsits soot with a ~ az CGI Iten ~ It of î'oxy ~ ene à une tem ~, grdt.lre co - ", - ~ e between 100 C and 400 C, av ~ ta ~ el) se", e.) t between 5 1 50C and 350C, from ~ refer ~ nce between 200 C and 300 C, the pr ~ partial oxygen supply of the gas co, nen ~ lt of the oxy ~ ene being at least equal to 3%
d '~ nospl, era, or 3,103 P ~, avanta ~ elJ ~ e "- ~ ntà4% .J'~" os, ~ l, era, either 4.103 pAeC ~
It is even desirable the partial pressure in oxy ~ ene is at least equal to 10 6.103 P ~ s, preferably "8 kg P ~ ls It is also souh ~ ble that the CGI Itact between the ~ az contains oxygen and the soot be maintained for sufficient time to burn 90% of the at least soot.
Indeed, completely, ~ l, t unexpected, it was found that rare earths 15 and not ~ "" ent the rare earth oxides, especially those due to cerium catalyzed the oxidation of mdti ~ r ~ s carL, o,) ées à te ", ~ tures also ~ q-5S05 that 100 C
(this value is a rounded value indeed, it could even be noted a oxidation at t6,. ", erections of the order of 80 C).
This p ~ en ~ - "è" e occurs only when the oxy ~ ene content of ~ æ is 20 SU ~ fiS; illl1116-1t high. The threshold from which soot oxidation depends to some extent the value of other para ~ tl ~ s. He believes when rare earth content of soot lifts off when the temperature rises again values ~ eses des fou-cl. ~ les, -, ellt ~ nnées ci ~ de ~ csJs ~
It should be noted that during the tests ~, receJents, this r ~ yén ~ rdtion could not be 25 observed because the oxygen content of the flash gases, ~, e ", 6nt is within usual conditions for testing such ~, rocess ~ s is cl, idle so as to maximize soot and is much lower than that required for this oxidation that we can q ~ i4r sweet.
The ~ .rocé Jé according to the invention can be used in many ways to reduce 30 ~ solid rejection missions c ~ bGne of all the sooty comhvstions and not ~ "l" ent of fuel engines ~ ni, lter "e.
One can thus d; ~, th, ~ .ler the continuous implementations of those which are intermittent.
In the latter case, if the oxidation of ", dtières c ~ l, Gn6es occurs as soon as 35 I'e "seems soot and gas is the te"", er ~ ture ~ déqll ~ te, it is ~, ref ~ rable that l, partial oxygen recession and t ~ l "p ~ r ~" re are kept pend ~ lt a duration SUIlisdml llel n long to oxidize all the soot prodvit ~ s to avoid that these Jel ~ ières do not accumulate or be rejected. So on average or 2 1 8 ~

st ~ tistiqlJe or continuously, it should that, for a defined period, the so "" ~ e time periods where the cGIlditiGns of the ~ resente invention are combined to ensure that the soot produced during the said defined period oxidize in their totality 5 Of said defined duration of ~, uen.l the illlpo5ge constraint to the prodlJctelJ system ~ and soot purifier. In the case where, cGm ", e in the particle filters, the time stay is ~ rand even infinite at the re ~ ard of their life expectancy, it is possible to provide said durations ~ ti "i ~ bn ~ ues. Said definb duration can then reach ten minutes or even 1/2 hour.
10 In the case of internal combustion engines ~ internal ion equipped with a filter for a long time defined is paid by pGriGdes penJ ~, t which loss of cl, ar ~ e occe ~ iQnnée by the filter can be relatively high. Tolerate the accumulation particles in the filters improve the quality of filtration. So there is a co "." ro ", is to be found.
15 Thus, it is therefore preferable to choose a defined duration which prevents the particles c ~ onées n'ocGAcion.) ent a loss of cl, ar ~ e greater than about a half ~ "bone ~ l, era. More pr ~ isél" ent it is desirable that 2/5 (or 2 / 5.105 P ~ sc ~ s), avanta ~ elJse, lead to 1/4 a ~. ~ Ospl, era (i.e. 1 / 4.105 P ~ s), ~ .reference 0.2.105 Pe ~ s, and, if we do not wish to improve the characteristics ~ ri ~ t; 4.Jes de 20 ~ soot dlion, more preferred, ltiellement 0.15.105 P ~ sc ~ s ~
According to an implementation of the present, Ite invention, it is possible to play the ~, ar ~ -, è ~ s of the engine and the i, dr ~ possible luction of a ~ az c ~ lenant of oxy ~ ene so that the constraints of t ~. ~ r ~ ture and content oxygen are filled with "~, iere that hangs ~ 1 a cycle called ~ European ~ (standard 25 EEC), there is no accumulation of soot in the filter.
It is equal, - 6nt possible to enslave the implementation of the program according to the .present invention at a loss limit value of.; ~, arye.
The time required for the gentle oxidation of a quantity, given by , -, dtière carLGnéa decreases 6vide ".lne" t with such "~ er ~ ture and content 30 oxygen. This gives a degree of freedom in the implementation of the .this invention.
The p, ése,) te invention pe, - "~ t to consider the use of sy ~", are less contraiy "an ~ s that b particle filter We can not ~, .l..ellt enva ~ er sy ~ tèmas having the c ~ ctgri- ~ ti ~ eu of cyclones or any system ~, ell "~ l ~ t une 35 auy "~ entalion of the duration of the residence time in an ar, lbiance where conditions prevail" éess ~ i ~ es, to the implementation of this catalytic system.
In these conJitions, if one wishes to eliminate the soot ~ ", ised by the sy ~ t ~ mes of comhl ~ stiQn, said defined duration is at most equal to the residence time of W095 / 18198; ~ 1 8 0 1 8 1 PCT / FR94tO1560 particles in the sp. that where reigns in a constant or inter ", itlente them conditions according to b pres ~, the invention.
We can thus envisage several implementations of the present invention.
According to one of the implementations of the ~, r ~ se, ite invention, a filter can be used 5 collecting the soot produced by the combustion engine, however in the event of need for air pulses, enriching in oxygen the gases of e ~ e ", e" t, ~ .e "" ~ tle from time to time lé ~ n ~ r ~ tiGn in the partial month of the fi ~ tre.
This enr ~ l, isse ", 6nt in oxy ~ ene of ~ az of flash, ~ p6", ent to reach a value where the procéJ ~ according to ~, - this invention is implemented is not 10 n ~ cess ~ ie for all engine operating modes and can be obtained by any means.
It can be ~ vt ~ ellt enriched by the i "j ~ tiGn of air in the flow of ~ az of ech ~ e. "ent. This air can av ~ ~ t ~ ously be heated by setting CGI Itact with Ji ~ l ~ relltes sources of heat and not ~ n ..., e, lt with hot parts du15 engine dir ~ ctemant or through ecl, an ~ eur of heat. It is also env ~ e ~ ble to use flywheels ll, e "" i ~ .les which seraie, lt heated ~ er ~ J ~ It la ~, ériGJe de non ~ éç ~ nér ~ tiGn of the filter by ~ æ d ' exhaust and restitution the heat emn.a ~ asi-, ée to air in char ~ e to enrich the ~ æ of echa ~ .e "-e-) t en oxy ~ ene ~ IJ ~ n ~, ériGJes of use of ~ océJ ~ according to ~ resente 20 invention.
In some cases, the simple mixing of outside air with the ~ az exhaust pel ~ and char, ltiGn of such "~, er ~ t ~ re and o ene content su ~ fisante to place in the area where caWytic oxyJ ~ tion takes place in t, onnes con-JitiG-, s.
The conditions prevailing in the turbo of a diesel engine are sufficient ~ Ites for obtain a corr ~ bustion of particles c ~ rl, onées which, in ~ general, penny; 'slow leturbo of turbos engines. In fact, completely unexpected, it was shown that the ad ~ ition of cerium, or any other rare earth, per -, etlait to avoid 30 any deposit ca.Loné in the parts of the turbo, ~ Gillt ~ -) t thus their implementation and their walk. And this, although the conJiti ~ ns of te "" ~ rdture re ~ "being in the turbo are very significantly lower than those which ~ r. "etlent in ~ ") dtiGn soot even ~ ol ~ e & rare earth.

35 The rare earths ~ re ~ ered are cerium, neodymium and l ~ nl, ~ e.
They can be used alone or in mixture with potel elements, adding co ", taken with other rare earths we can refer mutatis mutandis to the part Jescri ~ tio "directed more particular ~", ent on lanthanum.

WO95 / 18198 2 1 8 0 1 8 1 PCT / F ~) 4/01560 However, to date, the best results have been obtained by means of cerium and 1 ~ e. Alone or in combination with other rare earths.

5 In their for, ctiol) catalytic, these metals are, of ~ ference, in the form of their oxide IV in the case of cerium (and for the good rule for the ~, raséGJyme, but it is quite little écGnor, lique), trivalent oxide in the other eas.

It is possible; lb to use rare earth elements but, in this case, it is 10 preferable that the cerium eVou the It ~, donkey are the majority.

It is also possible to use mixtures of rare earths of the type prec6I. , ts, doped with non rare earth elements (cf. part on the do ~ e dula, l ~, a "e, which part is ~) spos ~ ble for any rare earth or mixture of 15 rare earth).

The rare earths can be introduced into the soot by i, lt ~ uduction in the derivative fuel such as their salts or their soils.
The introduction of CG ~, OS ~ based on rare earth (s) can be r ~ - ';. be 20 note ", -" ent by i, l ~ .duction of cG - "? Dare based on rare earth (s) in the d6slil fuel, to be introduced into the engine.

Another possibility is to introduce the rare earth (s) under various for ") es by the i, lt ~""ed; air area, and not ~" ~ ne ~ n air when it is mixed ~ é with 25 of eo gas ~, ~ pe ", e, lt of the engine, when a hd, ~ ion of ~ az of ~, app6-" is recycled in the engine. In this case, the corpus of rare earth (s) i "cor ~, or ~ s in recycled soot are introduced into the engine.

It should however be emphasized that the form in which the, or 30 les, rare earth (s) in the fillerJstibb. is not without effect on the size of crystallites and a ~ é ~ ats which are in the sub, size which plays a role in the catalytic capacity of rare earths resides within soot (cf. Dema,.
French patent N 92/14158 ~ J ~ JO66 b 25.11.1992 and entitled ~ ay-é ~ at eic oxide crystallites, ~, ol ~ t ~ ltion process and its use to reduce 35 combustion residues ~).
In addition, the lifespan of cerium salts and soils in a gold environment ~ ani. ~ .Îe is often weak and can be caused by bad results in the catalytic effect.
So when you want to use cerium it is ~, r ~ fable to use either the soil or WO9S / 18198 ~ 1 8 0 1 ~ ~ PCT / FR94 / 01560 -the salts subject of the European patent application ~ leposbe under the N93 / 304760.7 et ~ Jbli ~ e sous le N0575189.L '~ ddition exl ~ "", oranée au fuel for co "~ not stable dare ~, e""and to at least partially overcome the difficulties related to non stability ~ case of cerium salts 3 not s ~ il; s ~ es).
Before ~ eus ~ ", ent on Je ~ r", it) e the quantity of rare earths introduced into the engine of "a" iere that the content of rare earth (s) (in mass of metal COntffl lU) in soot reaches a cG level, - "ris between 1000 ppm and 30%
before ~ elJ ~ ement at least 5000 ppm of ~, reference at least 5% and av ~ l ~ elJs ~ ment at most 25%, of p, éfére-, this at most 10%.
On average during a cycb eu, o ~ éen, a value s ~ tisf ~ i ~ nte is around 5 to 10%.
It should however be emphasized that the form in which the, or the rare earth (s) in the fuel, is not without effect on the size of crist ~ tes et ay, é ~ ats which are in the soot, size which plays a role in the ca ~ e catalytic of rare earths present in soot (cf. DemanJe de French patent N 92/14158 .Jb ~ os6 the 25.11.1992 and entitled ~ approved ~ at ceric oxide crystallites, ~, process of obtaining ~ tion and its use to reduce combustion residues ~). Contrary to what one might have thought initial-- ent, this ensi ~ "e" .6, lt is valid not for the only cerium, but for all the grounds rare, alone or in melan ~ e, Jo ~ as or not, and not cGl - ", e only reserved with cerium. So in b ~ -s ~,. ~ E which follows and which deals with aJ, é ~ ats and cerium oxide (ceric) crystallites which cGn- ~, dare, cerium oxide plays the role of ~ .araJ; y ", e (like the verb ~ to love ~ is the ~ .araJi ~" -e of the first conj ~ French Pison or that ~ dominus ~ is the paradigm of (nth Latin declension) of rare earth oxides.
So it is ~ .référdble to shut up so that we use directly or indirecten.ent a; pe, ~, dts of ceric oxide crystallites, ~ le ~ dt ~ of which the most . ~ .I dimel, sion is cGIll ~ Jl ise between 20 A (2 n ~) G.,. Eters) and 10,000 A (1,000 "anGI" èl ~ es) de, l.référe "ce between 50 A (5 nanGI" et ~ es) and 5.000 A (500 nal, G, nbl.ds) and where the size of the crystals measured for the plane (1,1,1) by the technique of Debye and Scl, e "er is cG-" ~ rise between 20 and 250 A (2 to 25 nanG ", ~ es) of l, reference from 100 to 200 nano, nèl, es.
It should be emphasized that these measures are virtual measures and that would probably be more CGI. ~ s to refer to the width of the peak X-rays.
This is the reason for which the technique for measuring the crystallite size will then be indicated according to the technique of Sch6l, dr.

It should also be noted that the position zeros are not, except when this is eA ~ ressg ", e, lt indicated, numbers signi ~, cdli ~.
It is preferable that these ay, é ~ ats are topologically the closest possible soot, this is why it is desirable ~ 'i "l. uire in the cl, ar, ll, re 5 comblJstion or manufacture in situ said ~ yl ~ ats so that these ayléga ~ can form simullangfi, ent serve as soot gems.
To be e ~ icient, it is advisable to add, or to form ~ in situ ~, cerium in J form ~ yl ~ yats speci ~ iés above with a content of at least 10 ppm compared to carbonaceous fuel, from ~, reference 20 ppm more 10 advantageously ~ 50 ppm.
It is pr ~ f ~ rable that the cerium oxide thus formed ~ resents a ~ ranulG.n ~ ie such as d80 (-Ji ~, -bebe of the mesh allowing 80% by mass of the product to pass) or at most equal to 10,000 A (1,000 n & w ... al.es), from ~ reference to 5,000 A (500 nanG ", ~ es).
15 ll is also ~, real ~ that the d20 is greater than 200 A (2ollanGlllétres) and de, uréf ~ rence 500 A (50 nar, G ".ét, es).
The characteristics ~ 14, Jes of soot co, - ~ enant des ~, ~ ats below can play a role in the pr ~ s ~ .lt invention. It is therefore ~ .referbb that b granubl "~ ie dried out is such that the grain ~, rese, Ite a d2 ~ equal to at least 100 A eVou a d80 at most equal to 1000 A and which co, Itb ~ "~ en ~ at least 0.01%, before ~ freezing) sen) ent au minus 0.1%, preferably "at least 0.5% .la.J ~ ~ at according to ~.
invention.
Advantageously on average the content of rare earth (s) (by mass of metal content) in soot reaches a level co "", laugh between 1000 ppm and 30%
25 avanta ~ elJsel "ent at least 5000 ppm at least 5% plege and av ~ t ~ geus6ll, ellt at most 25% ~ preferably at most 10%.
In general, the sooty streaks of the amae whose b dso is cGm ~ Jris between 2000 and 5000 A.
According to an implementation of the present invention soot fo, ll.aes 30 ~, rese "~ e a total cerium content cG"". Rise between 1 and 5% by weight, preferably ~ 1.5 to 2.5%.
As it was ", e, Itb",) é above, av ~) ~ a ~ el) sem6 ~ 1t ay, é ~ at de crystallites is formed during the comhustion of fuel, or fuel, cedemier being ~ -h ~ tioned at least one CGm ~ Osé of cerium, ~.
35 tetravalent in the form of solutisn or sol.
It is also ~ alement ~, referable that the d20 is greater than 200 A (20 nanometers) and preferably 500 A (5onanGlll ~ es).

21 ~ 01 81 Élé ", in ~ s favoring this combustion (or re ~ neral, G") low temperature are the oxygen content and the content of co ", placed hydrocarbon.
As regards the oxygen content (which has already been dealt with above), it is preferable that the oxy ~ ene content is at least é ~ ale at 3%, from ~, rél ~ rence to 5 5% approximately.
Regarding the presence of CG ~ OS ~ S hyd ~ 6Gnes in ~ az ech ~, ~ 6. "e, lt, it is l, ref ~ rable that the volatility of com, vosés hydlocarbGnes, their gas content and their t ~,. ", ér ~ ture are such that, at t ~""~ ér ~ ture where soot is likely to be subject to corrosion (eg ~ l "~ the 10 accumulate in the filter by ~ bs), the content (I ~ Joll by mass) in co, .. ~, daring hy ~ ocal6On ~ s volatile in soot or at least é ~ ab .Jixiè,., e, de preferably a quarter, more av ~ lta "had ~ in ~ e" t half the mass on dry.
By volatiles, we mean all bs co, -, ~ sés h ~ J ~ s, n.Jt ~ --l "ellt those which exists in the ~ az of escape ~, 6l "6" t, which are in the form of gas at 600C, 15 av ~ lt ~ e ~ sel "6, d at 400C, from PréSérdnce to 350C.
It is desirable that these compounds hy.l ~ ocar6OI) és ~, rése, lt ~ llt a point boiling cGm, uris between about 100 and 400 C.
This re, J ~ nér ~ tbn intervenes in y ~ néral when the content of cG,. ", Daring hydrocarl, onés in gases is higher or é ~ ale at 10 ppm, preferably 20 greater than 20 ppm.

The best results - ~ tC are obtained with diesel fuels of which 95% by mass constituents distill under press,. a ~ l, éri. ~ ue to such "~, er ~ ture at less equal to 160C before ~ eus6, - ent to 180C and of which 95% by mass of constilants are volatile under ~ r ~ ssion a ~ t, os, Jl, éri4ue at 400C of ~ .ref ~ rel, this at 360C.
The process gives good results with high-content ga_obs.
aro, ll ~ l; p ~ e, than with the 9; 3'01QS with a high aliphatic content with the condition that the distillation constraints ~ 05 ~ eSCi- ~ eSS ~ JS are observed.
Most often the con ~, ~ sitions are CGll ~ pO ~ 5 of rare earth (s) liquids in the corditiG "s of use (not ~, .--, in ~ t ~ .." ~ er ~ ture ~ -lbi ~ e to the engine), in the form of sol (s), or dissolved in diluents hyd ~ ocall, onés, note ", me, lt fuels, including co ~ r ,, uris diesel.
Thus La Prés6, lte invention is particièlellleln interesting ~ lte for two kinds of - 35 fuel those whose aro content,., ~ Ti. ~ Eu is very high [content of derivative (s) alol "ali ~ eu (s) is at least equal to 1/5 before ~ el ~ se", ellt to a third], because it allows to use these fuels which without this invention would lead to too disturbing deposits.

2 1 8 ~ 1 8 1 In addition it is on the fuels (that is to say said mixtures) called paraffinics with a paraffin content of at least 30% of the effects are the sharpest. These fuels are studied for repor, J ~ e to news n ~ ", are more constrained ~ n ~) the &. It is desirable that for this type of composition, the ar ~ u ~ 6 content (by mass) is at most equal to 1/5 av ~ lt ~ eus6 ", e. ~ t at 1/10, preferably at 1/20.
The invention is particular ", ent well ~ -the ~ particle er" ises by fast diesel engines (by contrast ~ iGn to slow engines). These motors are for esse, ltiel used in l, ans ~ lts ~ r, ~ st.as, such as heavy goods vehicles (trucks, 10 ~ utoc ~, etc.), and light vehicles. By fast diesel engine we enter motors whose power ~ nce ma ~ i ", ale is reached at speeds of r ~ t ~ ti ~ n at less than 1500 revolutions / minute; avanta ~ e ~ lse ", it is at least equal to 1,800 rpm.
A particular implementation "ent avdllt ~, euse of the present invention 15 c ~ "if ~ e in one ~, rocédé of filtldtiGII of the gæ of an engine with internal filling.
This process which consists in:
introduce at least one derivative of rare earths or a mixture of rare earths with a C ~ llt ~ dti ~ cG. "~ rise between 10 ppm and 500 ppm (by mass), preferably between 20 ppm and 200 ppm;

collect the soot produced by the comb ~ lstion engine on a filter internal, such "~, er ~ ture of gæ ellt ~ ant in the filter being c; l, idle in the interval 100C-350C (the zeros of ~ ositi ~ n are not numbers signi ~ ic ~ tif ~);

and Allow the soot to accumulate until reaching a diet where a h ~ tiGn notable of the soot arriving is compensated by the comb ~ stion of soot in the g ~ te ~ u of soot on the filter and do not provide any regeneration, as long as the loss of cl, ar ~ e provoqlJées by soot does not eYc ~ Ja value ~ .Q jsie in advance and is not ~ 400 millibar.
The loss of ~, ar ~, e below DessJs n'i, ~ r ~, ore ore the loss of cl.ar ~ eo ~ ri ~, -, ée par35 the filter not cl, ar, ~ soot, loss of ~, ar ~ e which in ~ él, éral is less than 100 millibar, and very often less than 50 millibar.

WO 9 ~ i / 18198 2 1 8 0 1 8 1 PCT / FR94 / 01560 For reasons not e "tièrei" e "t eluci ~ ées the metallic filters give ~
resu ~ ts particularly good, or more eY ~ ff "-ent re ~ en ~ ralions particular ", frequent.
The filters give better re ~ u ~ ts after 3, pr ~ fére,) this 5 cycles of S re, a ~ "eration.
So su ",, enal ~ te we could cor.st; ater that there was, en ~ é" éral, no need to cause re ~ enértti ~ s when res ~ rt ~ it the conditions below dessJs ~
The ~ é, er ~ ti ~ n allo ~ ene (or exG ~ ene) is in r ~ the ~ generally not useful and should not be considered ~ ée only when one wishes to maintain a level of loss of char ~ e 10 particularly low (generally less than 200, even 150 millibar).
As an alien regeneration, it is therefore advisable to consider re-generation realized by overheating (to bring the point to a t ~ ,,,, u ~ rdlure month equal to 500C before ~ suitably 600C) no ~ ulo ~) ~ not punctual, and not global across the filter; this possibility is only there because, according to The invention, a point overheating '~ does not cause a re ~ en ~ rttiGn ~ lobale and complete of the fife.
The occasional overheating can be achieved by any known means of I, ~ G ~ me by trade, such as mbro-resi;, t; ~ nce (s) r ~ p ~ ties on the filter surface, metallic particles ch ~ uff ~ e ~ by eddy current, mini-arc or equivalent.
The mode of wire ~ ttiGn according to the invention does not fon ~; t; on..e Jénéral that penJant a part of réy;,., ace of an engine, because some of the regimes eny6 ~ J ~ t ~ az of a telo ~, ert ~ .Jre a month é ~ ale at about 500C (two chfflre if ~ --ificttif ~) which ipso facto performs a re ~ en ~ r ~ tiGn pr ~, essive and often complete the filter.
It should be noted that the t ~. ". er ~ ture of ~ æ ellt ~) ts in-the filter may vary large,., e, lt inside the domain of tem ~ .érdture 100 ~ 00C. These v, .ridtiGns, which can be deliber ~ l "ent provo ~ luées, favurisellt la ré, a ~ n ~ ration and ~ .er", etlent maintain a low value pressure drop.
We can av ~ lt ~ euser "~" t choose the ~ -ositiGn of the filter so that such .. ~, ~ r ~ ture 30 filter either for the most ~, ~ .of part of the time possible at such "perdt ~ re cG, .. ~, rise in the mad, ~ tl ~ here-desslJs As indicated above, the rare earths ~), efer ~ es are cerium, I ~ IU, anc and tale mixtures,) ~) t of cerium and bnthane. The content b plus common rare earth (metal) fuel c ~ lt ~ bare is c ~ - ",, ise between 50 and 35 150 ppm.
According to the present invention, the rare earth content of the fuel can be chosen.
so as to adjust the pressure drop to a value chosen in advance. We can WO9S / 18198 ~ 8 I PCT / FR94 / 01560 also play on the surface fill, ~ te, and everything remained, lt in the field sp ~ ifi ~ ci ~ essus la te, - "~ ér ~ t.Jre.
This value cl ~ oisie in advance is preferred,) this cG. "~ .Rise between 100 and 400 millibar, of ~ ference between 150 and 300 millibar.

To obtain "i. Such resl ~ lt ~ ts, it is ~, ref ~ r ~ l, that the rare earths present, ltes in soot presents- Itel It a conce, It ~ dliOI I between 500 ppm and 10%, of ~, reference ~ n ~ e between at least 1000 ppm (mass of metal contained by ra ~ pGI I at total mass soot, including the comos they have a.lsGrl, és) and at most 5% in 1 0 average.

In most cGr-merci engines ~ 'ized to date, it is downstream) ta ~ e ~
di-lt-oduire the rare earth, or the melanye of rare earths, with its procession impurity (s) and adjuvant (s), at a wfi "content, rise between 10 and 1000 ppm in the fuel. These values are eA ~ ri .., ~ es metal cGnt ~ l) u. Before ~ elJsel "ent, contents of 20 to 200 ppm are used, l ~ rence of 50 to 150 ppm.
Some internal combustion engines, such as gasoline engines and some die6els engines under test and development --- 6 "t, produce or dov.di6ntproduire, less soot. Insofar as only the regenerative effect of the filter 20 is recl) erc ~, é (and not the improvement ~ tiû "~ general of the comblJstbn), that ~, er -., And, of reduce the quantities of rare earth or of rare earth mixture to be introduced;
in fuel, when this mode of ~ t, cduction was preferred; and a more ygl, eral way in the cl) ~, combustion lbre. This redaction is done at ~ roraLa of the production of soot to maintain the rare earth content, or the 25 rare earth melanye in the ~ Jites soot.
It is av ~ t ~ ge ~ x that the torch under which the rare earth, or the mixture of earths rare is introduced induce the formation of ~, é, c ~ ats of earth oxide crystallites rare, or a mixture of rare earths, where the most ~,. ~ .de dil - e - sio ~ of said aggregate is col "~, rise between 20 any ~ ufi ~ s and 10 000 ~ y ~ ul - s, de ~, reference between 100 30 and 5,000 years ~ c -, s, for which the size of the crystallites is reduced between 20 and 250 ar, y ~ cn) s, de ~, reference between 50 and 200 year, ~, ~ on-s.
The introduction of co ", placed on the basis of rare earths, alone or in., Éla, ye, can be r ~~ e no ~. "., en ~ by the ilt, ~ Juction of con ~ s based on rare earths, alone or in mixture, in the fuel of ~ i ~ é to be introduced into the engine.
Another possibility ~ 6 is to introduce the rare earths, alone or in mixture, under various ~ or ", es by in ~ er", ediary of air, and note ""., ellt air when it is mixed with engine exhaust, when a fraction of the gases 21 80I 8 i chess ~ p6 -, - ent is recycled in the engine. In this case, the co.
rare earths, alone or in melan ~ e, i "cGr ~ orées in recycled soot are introduced into the engine.

5 One of the most pr ~ ti ~ ues to introduce the rare earths, alone or mixed, in the circuit of the engine consi; .te at i, lt ~ uJuire in the fuel either in the form of salt, or SOU8 in the form of soil. These cG ". ~ Daring, salts or soils, conl ~ GIldnt before ~ geuseme-lt products not harmful to the corr ~ bustion or for the env ;, onneloent.
10 Thus, it is ~, r ~ ler ~ ble that the salts or soils are prepared from CGI ,, poSéS h ~ nJ ~ occ rl, onés such as J'acWe carl, Gné salts, they are of the type carboxylic or collar type "placed at hyd ~ o ~ mobile ene such as for example acetylacetonates.

15 We can ~ ab -, - ent envisaged ~ aar CG.Il ~ acid type sulfur-based such suHuric acids (suHates of alkyl or aryl acids) or suHonic acids. All of these .Jer - i6rs acids have the drawback au ~ ", enter the sulfur content of the fuel.

20 In a way ~ enér ~ b for the rare earths having ccl, .n, e valence most high valence lll, the aciJe c ~ bcxylic salts of C2 to C20, preferably from C4 to C1 s, are among the best ~ d ~ t ~ s in this usa ~ e.
For cerium the derivatives of cerium IV are ~, referred because of their stability and of their ~ titude to making few particubs 25 ll is ~ .refrable as rare earth oxides or mel ~~ as earth oxides few are stable in fuel. Cerium is the rare earth ~ refel ~ e, alone; or in combination. In fuels, cerium can be introduced either in the form of soils or in the form of various salts provided that these last are sufl, samn) in ~ stable in b middle. We can note ~ ..r -ent quote 30 salts subject of the --- a, n ~ e patent eu-op ~ o- ~ ne ~ 05 ~ e UNDER number 931304760.7 and ~ Ibli ~ e under b number 057 5189.

Indeed, in a complete way - "6" t su- ~, re ~ te, it could be seen that when using ~ tif ~ based on transition metals (i.e.
35 metals including one of the sub-layers d is being rem ~ s ~ e) r ~ "grdlions at low te,., temperature were either nonexistent ~ rltes or gave rise to infla """brutal aliGns leading to te", l, grdl.Jres 61OV6OS suscelltil, b ~ d'er, dom ", have filters.

~ 1 ~ 0 ~ 81 On the contrary, in the case of él ~ ", en ~ s Add; t ~" born of derivatives based on grounds rare, we reach quite fast ", ent, after an accumulation phase in the filter, a state in which the amount of soot arriving on the filter is cGr "thought by no ", many random but not brutal comhustions, having taken place in the mass of soot accumulated on the filter.

It follows thermal effects not very marked as well as v ~ ridtiGns of loss of charge b ~ Auco ~ ~ p plus f ~ ib'es Thus, we could ", ollt-er that the use of additives based on elé, -, e" t ~ land rare leads to a double av ~ ta ~ e:

- first, the limitation of thermal excursions (due to the regener ~ raliGn of the filter) p6r ", and of conse, ver au, na ~ gliau filtering the intg, ~ -alilé
of its pro ~ .rieties and not ~ "", ellt its e ~ i ~ cP6 filtration; the system has a more sustainable and better ~ icaci ~ é;

- secondly, the con ~ "GIte" ~ e ~ t in ~. presence of additives based on élé ", ents of rare earths ~, er-" and a ~, more flexible estion of phenol "bnes loss of cl, ar ~ e; indeed, in b case of ~ JJ; '; ~ s based on the elements metals of the ~ -sition (not ~ .. "ent copper and iron), re ~ ener ~ tions are random, violent and brutal, the key losses evolve so very abrupt. This occ ~ cionne varidliGI) s plJis ~ -, that of the engine and harms safety and cGnf ~ JIl driving and good fol ~ iG "nel" ent of the motor; on the other hand, in the case of Ad '~; ~ HS based on él ~ "enls des rare earths, the ~ é ~ enér ~ ions are weak ampli ~ ds which reduces the effects on charye loss and thermal effects. The pressure drop due to the filter is st ~ hilice and can be managed without penalizing security and Driving pleasure.

According to one of the preferred modes of the ~ invention, it is possible to use the lanthanum derivatives to implement the ~, invention resente. This led to putting at the point of the derivatives of l ~ e as well as other rare earths h ~, ~ es By means of a method for reducing the soot ~ n) emission of a soot internal combustion in which the flowing gases are passed, ap ~, ament through WO 9Stl8198 PCT / FR94tO1560 of a particle filter and into which are introduced into the corrbustiQn an additive containing lar ll, &) e.

According to one of the modes of implementation of the ~, invention resents, the lanthanum is 5 added to the fuel in the form of a salt or a stable soil.
The use of rare earth co, n, - e adjuvants of comhustbn has been described since lon ~ Jte, nps in the prior art, but the lai ~ U, al.e has never been cited that i "ciJente, or rather iqcciJent ~" 3, as a member of this family.
10 More recent ---- n6nt, in an exhaustive study r, .enée at lnstitut rrançais duPétrole on Ji ~ f ~ rel ~ your rare earths and on their ~ titude to catalyze the oxidation of soot, Mr. DESOETE a ~) ~ have ~ é that the lal ~ U, donkey had no ~ .re ~ riety of catalyzes on carbon particles.

15 This article published in an year and entitled ~ Catalysis of soot corr ~ h ~ stbn by metals oxides ~ dated February 1988 and published under the reference 35991 (available on de-nar, I public) n, o lt-e cla i. ~ me. ~ t in his fi ~ ure 10 I'abse "this effect of the oxide de lai ~ tl, ~ -e.

20 Maniare completely su ".rel-ante, soot ~ er", ées by the i., LruJuction of compounds based on ~ nl ~ ana in combustion engine circuits internal, and n. ~ tamn, ent of diesel engines, ~ rése "tellt la pro ~, riété d '~ tre significantly more inllam,., ables, that is to say presented a temperature J i "flam", aliGn lower, than soot prb ~ without additives.
The intro ~ uction of cori "~ os ~ s based on lai ~ tl, donkey can be r ~ sée r, ot ~.". "Ellt by the i, lt ~ uJuGtion of CGm, uOSéS based on lantl, donkey in the fuel intended to be introduced into the engine.

30 Another possibility is to introduce the l ~ n ~ ai ~ e under various ~ or "~ 05 by l'i "lel .., éJ ~ ire air, and not ~ ...., e. ~ t air brsqu'il is melan ~ é with ~ az of flash, ~, e, .. ent of the engine, when a f ~ tbll of ~ az of flash, ~ pe --- ellt is - recycled in the engine. In this case, the con- ~, o ~ s of l ~, tl, ~ e incG- ~, orés in the recycled soot is introduced into the engine.

One of the most popular means of introducing l & a, into the circuit of the engine consi ~ the i "l-uJuire in the fuel either in the form of salt, or under soil form. These cG, nposed salts or soils, before ~ ablement include products not harmful to the corrosion or to the environment.

Thus, it is preferable that the salts or the soils are ~ r ~ prepared from 5 compounds h ~ J ~ l ~ born such as salts J'a ~ iJe csrboné, they are of the type carboxylic or cG type ", placed at hyJ ~ o ~ bne mobile such as for example acetylacetonates.

We can also consider co "" ~ daring acid type sulfur-based such 10 that suHuric acids (sulf ~ your alkyl or aryl acids) or - suHonic type acids. However, these latter acids ~. The disadvantage auy ", entar the sulfur content of the fuel.

In general, the J 'iJe c ~ 60xyl salts of C2 to C20, 15 preferred ~ nce from 4 to C1 5. are among the mbux ~ ~ t ~ s for this use.
To obtain a good catalysis of the combustion of soot, it is necessary to ensure in soot a conce, lt ~ dt ~ ns ~ tisf ~ i ~ ante du I ~ IU, donkey and its possible potent adjuvants; ~ 'is ~ tion; this concentric ~ dliGn is forward ~ elJs6m60t between 500 ppm and 10%, from ~, reference between at least 1000 ppm 20 (mass of metal cGnt ~ llu by rdppoll to the total mass of soot, y CGfi) p.is con ".osés they have aJs ~ rLés) and at most 5% on average.

In most co """engines erci ~ lis ~ s to date, it is av ~ lta ~ 3eux truJuire lalltl, ~ e, with its procession of impurity (s) and adjuvant (s), to a 25 col content "~. Between 10 and 1000 ppm in the fuel. These values are ex ~, laughed, born in metal contel-u. Av ~) ~ ye ~ sement, we use contents of 20 to 200 ppm, preferably 50 to 150 ppm.
Some internal combustion engines, such as gasoline engines and some diesel engines under test and development .6me,) t, prorl ~ isent or should 30 produce, less soot. As far as ob only the effect of re ~ enérdtiG "du ~ iltre is sought, é (and not the general improvement of combustion), that ~, er,., and, of reduce the qu ~ lt; s ~ l & ltl, ass to introduce; in fuel, when this mode J'i.lt ~ ction was privileged; and more generally in the c ~ bre of comb ~ stion. This reduction is done at the point of production of soot for 35 ", ai" ~ enir the content of b "tl, ~, e in lesJ ~ es soot.
It is av ~, '- ~ e ~ that the ~ elm under which the lanthanum is introduced induces the fo, l, ldtiell of aggregates of crystallites of oxide of l ~ ltl, donkey where most y, anJe dimension of said ay ~ yal is co ",, c rise between 20 anga ~ o, -, s and 10 000 al ~ y ~ rul ~ s (2 and 1000 nm), from ~ re ~ erence between 100 and 5000 angstroms (10 and 500 nm) for which the size of the eristallites is eG "". rise between 20 and 250 year, a ~ t ~ u ", s (2 and 25 nm), of ~ ,, é ~ erence between 50 and 200 year ~, ns (5 and 20 nm).
According to the present invention, it has been éabl-, e-lt IIIG nlb that the la "l ~, a,) e was a 5 suseeptible element of ~ telltialiser, or to be ~ t ~ ltialized by, other élé ", e, lt ~
no ~ l ~ ", e, lt su ~ l) tibles of eatalyser oxy ~ tions of products e & rL, on ~ s and those inducing deposits in the network! eristallin of the oxide of the nl ~ donkey.
It was thus ", o, lt ~ é that the élel" ellt ~ of transition, ie metals of which one of the sub-d eouehes is in the course of filling, gave with the 10 lanthanum marked synergistic effects. This synergistic effect is also highlighted with other ~ l ~ rnen ~ s eouehes f en eours de repl ssn ~ e and "otar"", el d avee other rare earths there co""risl'yttrium.
The most marked r ~ sult ~ ts are eeux due larltl, ane ~ ci ~ s au ", an ~ anèse, with copper, eobalt and iron. also have a special interest 15 other rare earths, including ~, ris the yttrium, alone or in admixture.
The ltl content, ane ra ~ J ~ JGilé à la so ", l" e des élg ", metallic enls eGIltellus in the adjuvant is in ~ "~ ral eo" ~ rise between 5% and 95%. A ~ t ~ gelJse ", ent it is at least 50%, preferably 80%
The elements ", e, lts ~ ote, ltialisant, or ~, ~ tent; ~ read by, bl ~, ~, donkey are introduced 20 eo ~ r "" e can be eet element.
As eela was ", e, ~ tio ~ é ~ réeéd ~, .." 6nt, another goal of the ~ r ~ feel invention is to provide a ~ .roeédé which ~ l ~ the one ~ é ~ Jé ~ ératbn that we can q ~ ior of low t ~ l "~ rdture filters partieules 25 This object is achieved by means of a p, oc ~ Je u ~ ilisant les cG ", based on the, ltl, donkey mentioned above ~ essus.

This proc ~ J ~ consists in:

- introduce into the fuel a lanthanum derivative such as s ~ fi ~ ci-desslJs to a concell1.dliGn c ~ "p, ise between 10 ppm and 500 ppm (by mass), de, uré ~ erence between 20 ppm and 200 ppm (metal cGnt ~ naked);

- collect the soot produced on a filter; ~ es by the combustion engine internal, such "gas péralure e ~ ltl ~ lt in the filter being selected in the interval 100 400 C (in this Jes ~ i ~ liGn the zeros of ~ itiOil are not significant figures, except when this is, ureois ~), and let the soot accumulate until reaching a re ~ ime where a f ~ a ~ lion 21 8 ~ 1 81 WO 9 ~ / 18198 PCT / FR94 / 01560 notable of the soot arriving is compensated by the combus ~ ion of the soot in the g ~ te ~ l soot on the filter and do not provide any forced re ~ néraliGn as long as the pressure drop caused by the soot does not value chosen in advance and a ~ ta ~ euse ", ent n'q ~ cé ~ L ~ nt not 500 millibars.

Indeed, according to, vrés6,) te invention, we could, "o" bar that there could be r ~ enér ~ iGns to ten) ~ erdtlJres as ~ sses as 100 C approximately. During of a motor cycle eu, op ~ 6 ", there may be vari ~ liG" s bruWes temperature in ~ az of pe ~ pe ", e, lt which can, without reaching the value 10 max ", um below desslJs (ie te" ~ per ~ minimum fatal ture to the filter (s)), per ", and obtain partial or complete regeneration.

The following nonlimiting examples illustrate the invention.

EXAMPLES:

A- Description of the con ~ jtlons ex ~ erimen The engine used is an abnos diesel engine ~ héri ~ -I, with four cylinders, indirect injection, of 1.696 liters of displacement and developing 50 kilowatts to 4,400 Rotations per minute. This engine is sold under the Volkswagen brand.

25 The filters used are cordierite filters produced by the Company Corning, type EX 47 (5.66 inch dian) ~ e, 6 inches long, with a density of cells of 100 cpi / 17 mil). Each additive has been tested wr a filter new. We continuously measure during the tests:

- the pressure drop linked to the filter (loss of cl, ar ~ e between inlet and outlet of the filtered);
- the ter "~. ~ rdture of gases at the inlet of the filter;
- the te "", ~, dl.Jre gas at the outlet of the filter;
- carl one monoxide emissions.
The tests are conducted at 2000 revolutions / minute in May., Ten ~ lt cor, st ~ lte la te, n ~ .ér ~ ture of gas at the inlet of the filter in b time. The trials conducted at a ~ l8ol8l ~

tei "~ 250C mineral are re ~ ilés below but resuh- ~ ts similar have been obtained from other te, npéralures.

The tests were r ~ e '; s noted note ~ .n, ent with:

- an iron-based additive with an oil content of 20 ppm (mass);

- a copper-based additive; the copper content in the fuel oil is 20 ppm;
- two ~ dd ~ based on cerium and rare earths; the content of el ~ - "e, lts des rare earths (cerium) in fuel oil is 50 ppm.

Taking into account the ", respective molar asses of the elements", then, the contents 15 molars, or more q ~ J ~ n, e, lt atomic, are roughly of the same order for all ~ additives namely:

iron: 0.36 moles / 1000 kg of fuel oil copper: 0.32 moles / 1000 kg of fuel oil;
20 cerium: 0.36 moles / 1000 kg of fuel oil.

B - R ~ lt ~ t ~

Fremnle n 1 case of iron-based addiffl Resuh ~ ts are repo.lés on Figure 1. This figure gives on the one hand the evolution of the pressure drop in drilling, time as well as the content of carl oxide, ~ "e in the gas leaving the fuel, as well as the evolution of te "", gas temperature at the outlet of the filter in f ~ "~; tion of time. We col, ~ tale that the 30 p ~ riGJas of accumulation can reach a duration of 35,000 sec ~ -Jes. The loss of cl, ar ~ has reached ais ~ ", e. ~ t 300 millibar. During the re ~ nérdli ~ s which cGrl ~ sporlJent to the sudden decrease in back pressure, we cGI ~ slale a strong at ~ me ~ taliGn of the content of "- ~ cwoxide ~ rbGne for ~ az at the outlet of filtered. Simult ~, en, e-lt at these v ~ tions of content in ", c ~ lone onoxide, we 35 co "st ~ te a very abrupt augn, ent ~ tiGn of such" p ~ rdture of gases leaving the filter, with such "~ .erah ~ res up to 700 C, even 800 C, while the te "" ~ eralLIre of gases at the inlet of the fiitre is only 250 C. The v ridli ~, of the back pressure is very brutal. You can lose 250 millibar very quickly n when WO9S / 18198 ~ 8 1 PCT / FR94 / 01560 of these regeneration phases, and the duration of the accumulation zones while as the amplitude of the back pressure varialions seems to vary so random. These graphs "~ highlight the co""oi Len) ent ~ toire and brutal réy ~" eralions, which leaves sul ~ Joser that the engine will probably be affected5 by these bnusques v ~ rialions of counter ~ ~ ressio "in downstream.

In this example, the iron-based additive is iron-ecene.

~ 180181 Fremn / en 7: case of the copper-based additive The copper used is a cupric car6Oxylate. The results are reported on the figure 2. This figure gives on the one hand the evolution of the back pressure in 5 funtiGn of time as well as the content of ", c & r ~ onoxide, one in the gas output of the filter, and the evolution of the tem ~ .é, dture gas at the filter outlet and this in fo n ~; tiGl I of time.

We note that the accumulation periods can reach 54,000 seconds, 10 is almost 20 hours. We cor, st ~ te a loss of cl) arye, or back pressure, up to 350 millibar. During regeneration ~ ns that cones ~ GI) tooth at the abrupt decrease in the loss of el, ar $ Je, on cor, st ~ te a strong auy, oentatiGn of the content of, nono ~ yde of c ~ r ~ one in the ~ æ at the filter outlet. Along with these varidli ~ l) s of the content ", onol- ~ rde de czrL ~, e, on cor, stala une très 15 abrupt augmentaliGn of te ", peralure of ~ az at the filter outlet with te "") eralures can reach more than 800 C, while the tem? erdture of ~ az at the inlet of the filter is only 250 C. La ~. ridli ~ n of the back pressure is very brutal. You can lose 300 millibar very quickly during these ples ases rgyénér ~ tion. The duration of the accumulation zones just like the arnpl; ~ ude des 20 vari ~ iiGns of back pressure seem to vary randomly. These ~ raphes put in ~ viJence the CG "~ pO ~ LEMENT random and brutal of these r ~ y ~ nér ~ iG., s, ce which suggests that the engine will be affected by these sudden varial ~ l) s downstream back pressure.

~ n 3: case of a ~ dditit ~ cerium base (compound described in European patent application deros4s under h number 93 / 304760.7 and published under the number 057 5189J

30 Res ~ lt ~ ts are ~ e ~, G, les on the fi ~ ure 3. This figure gives on the one hand the evolution of the back pressure in ~ "diGn of time as well as the CO content in the gas leaving the filter, and the evolution of the te "" ~ temperature of the gas leaving the filter based on time. We cor, st ~ te a ~ riGJe of cl, ar ~ ae, - ant of the filter 25,000 secor, Jas. Beyond, we CGllStd ~ that the counter ~, r ~ if ~ n is practically 35 stable. This counterpressure stabilizes in the vicinity of ~ 200 millibar. At ", G" -ent reyénérdlions which cor, espondenl d very small decreases in the back pressure (infériùres to 50 millibar), we conslate vdri ~ lions of the content in carl oxide, one in the gases leaving the filter. These varidlions testify 21 80 ~ 81 constant regeneration activity over time. Along with these goes, ialions of the carbon monoxide content, there is an au ~ mentalion ", od6rée de te"") gas lining at the outlet of the filter with ten", can reach at most 400 C, and this for a te "" ~ éraLure gas at the entry5 of the 250C fittre. These y, ~ l) es ", t ~ tlent évi-Jence the con" uG, t ~ ", ~" t at a time ", odre and permanent re ~ ngrdtions which leaves su ~ .pose that the engine and therefore the violent conduct will not be altered.

10 ~ mole n4: exempl ~ of an addiffl ~ b ~ s ~ d ~ c ~ rium sol.

These res ~ tc are lepG, Lés in Figure 4. This figure gives on the one hand the evolution of the back pressure in fon ~ Lio "of time as well as the content carbon monoxide in the gas leaving the filter, and the evolution of the te "" ~ er ~ ture 15 of the gas at the outlet of the filter in time; There is a p ~ riGde of loading of the 45,000 second filter. Beyond, we see that the counter prt ~ ssiGn is practically stable. This counter-press ~ we st ~ ilise the neighbor "a ~ e from 200millibar. In the IllGlllenL of ~ é ~ nérdtiGns which c ~ spond ~ nt to very small decreases in back pressure (less than 50 millibar), we co-, ~ t te 20 v ~ ridlions of the content of rnonoxide of ~ rLo - e in the gæ at the outlet of the filter. These v ~ ridLio., S show a cost ~ re ~ engrdLion activity in the time. In parallel with these v riatio.) S of the content, .. onoxide of c ~ bo - e, oncor, st-ate an augmentGe mGdéré te, .. p ~ rd ~ re gases leaving the fittre with such "p ~ ralures which can reach at most 350C, and this for a 25 tem ~ gas temperature at the entrance to the 250 C fittre. These yl ~ 1, are Ill ~ tlent ~ vi ~ ence the neck "~ .G, Iff, .. ent at the same time .., cdgré and pe""~ ellt des r ~ y ~" gr ~ tiG.-s, which leaves think that the engine, the safety and the driving system are not altered in any way.
The number of fine particles for ", ~ es is significantly lower than that of 30 examples precede.

F ~ err ~ le 5: e ss ~ is on engine bench in isoregime 35 Tests have been carried out on a new F8 ~ 706 type engine of 1870 cc, and the particulate filter used is an EBERSPACHER particle filter number 76 ~ 6000415. This filter is equipped with two ll, er .., ocouples, one upstream, the other downstream. The tests were carried out on particle filters which have undergone ~ 1 80 ~ ~ 1 ~ lusi ~ u ~ s loadings and several ~ s réy ~ néralions. Indeed, the first effects are relatively er, ~, Jes.
- For each additive: a new particle filter (FAP) is used.
- The particle filter must be initially st ~ hilis ~ t, that is to say, it must 5 undergo a minimum of 3 cycles: enc ~ asse ", 6, lt and ré ~énéraliG".
in ~ assefi, 6.lt on point 1500 rpm 3/4 cl, & r ~ e, cl, & r ~ 6r "ent de filter ~ particles at 70 ~ soot;
réy ~ n ~ rdlion on point 4000 rpm, flash temperature, a ~. ~ Jen, e, lt:
600C.
- On each particle filter, ~ enJ ~ It the current stabilization phase of fouling "e, lt and on the point of fouling", the law is noted: mass of soot J ~ daring: f (~ P FAP) (the relationship is constructed by d ~ l-ose and successive weighing of the filter element.
The self-test ~ enér ~ tiGn is performed cG ", -, e follows:
- Initial conditions:
Ie particle filter is enc-assé to 70 ~ soot, before the test, the particle filter is cold (l6, n ~ .ér ~ ture ~ 6i ~ lte).
Ies tests below are tests on stabilized particulate filters (FAP).
The tests are carried out in isoregime, the regime being ex ~, ri- "é in nonlbre of 20 revolutions per minute.
The rfflJ ~ t ~ obtained either without additive, or with an additive based on various salts of rare earths introduced into the fuel in the right way, unless indicated aut ~ e ", 6l, t, of 100 ppm of metal contained" u, are collected in the tables following:
25 the filters are previously cl) aryé of particles under conditions where they accumulate even in the presence of rare earths. these con JitiGI IS are:
1500 rpm;

3/4 of the full cl, arge;
ricl, esse du .., élanye between 0.8 and 0.9;
Oxygen content of the gases: between 2 and 4%;
Ies particle filters are cbar ~, é to 70 ~ soot per filter.

35 ~ ri ~ on f ~ see rl ': 3llt ~ ré ~ enér ~ tion. ~ C ~ llies ~ vec lln ~ 7- ~ 1st ~ rl ~ itiv ~ ~ 1 Ir motel 1- f8q ~ 706 WO 9 ~ / 18198 PCT / FR94 / 01560 The test lasts approximately 130 minutes (8000 seconds). We were able to note that when there had regeneration pressure toWe se, -, was at a value inside 200 millibar approximately during the rest of the test. The pressure drop related to the sole fitter is in the range of 50 to 100 millibar.

Isor ~;, .. e The autoregeneration tests are carried out on three isoregimes in the order: 2500 -1500 and 4000 rpm.
The engine is started and adjusted to the operating point (example:
2,500 rpm PME (Effective Average Plow: 0 bar) without delaying te ", péral, Jre of the engine after 10 minutes, begins the ec ~ uisitiQn of the pfe, -, ier point.
The test is carried out by increasing the load every ten minutes following steps predelines (PME: 0; 1; 2; 3; 4; 45; 5; 55; 6.5; 7; 75bar).
15 The effective average pressure (PME) is given from the couple by the PME relation = (40 x ~ x couple) / displacement.

Once the particulate filter is loaded, the engine is stalled on a ce. ~ I..e speed and so as specified above. the load is increased p-og ~ ssively in 10-minute increments 20 (incr ~ ", ent of the order of 9 Nm per step) until the value of the order of 100 Nm once the regeneration obtained the values of the di ~, t "are determined, the variables just before triggering.

F ~ empty The engine is run empty at the desired speed.

No additit tests T. REGIME ~ ch. T. PME dp 02 HC CO With upstream FAP or FAP without additit rpm CC bar mbar% ppm g / h ppm g / h 1500 503 4.15 769 - - - - - without 2500 432 382 4 15 853 9.2 without 4000 451 419 1 55 1154 11 2 without SUBSTITUTE SHEET (RULE 26) WO95 / 18198 2 i 8 0 1 8 I PCT / FR94 / 01560 T, ~ RI F ~ U 2 VACUUM TEST
with 150 ppm (metal content) of c ~ rium salt (octo ~ cerous) with T. REGIME ~ ch. T. PME dp 02 HC CO or upstream FAP without FAP ad-said - rpm CC bar mbar% ppm g / h ppm g / h 800 98 79 0 240 17.50 138 2.8 30012.3 with 1000 104 87 ~ 0 258 17.45 62 1.5 23011.5 with 1500 126 114 ~ 0 360 17.70 38 1.60 25021.70 with 1500 125 119 ~ 0 426 17.55 27 1.1 240 1.2 avocado 2500 239 227 ~ 0 115 615.55 58 3.8 32 042.6 with 4000 362 336 ~ 0 113 313.45 46 4.6 22 044.7 with R ~ t ~ t ~ le l ~ ne The results obtained with an additive based on lanthanum octoate introduced into the fuel at a rate of 100 ppm of lanthanum are ~ sse, - ~ blés in the tables following:
T ~ F '~ U 3 T. With REGIME T. ~ ch upstream PME dp 02 HC CO or FAP FAP without additive rpm CC bar mbar% ppm g / h ppm g / h 1500 460 388 6.4 705 5 10 0.4 150 12 with There is no r ~ q ~ u ~ r & tion 1500 d 2g5 241 ~ 2.5 663 13.5 46 1.9 160 13.4 with a 2500 371 331 ~ 3.5 821 10.8 29 1.9 140 18.3 av ~ c b 2500 285 251 ~ 2.2 943 13.8 32 2.2 170 23.1 with 4000 431 383 ~ 1.6 1060 10.9 8 0.8 220 46.8 with SUBSTITUTE SHEET (RULE 26 ~

2 1 80 1 ~ 1 WO 95/18198 PCTlFR94 / OlS60 TARI F ~ ll) 4 FS ~ AIS A YIDE WITH LANTHANE SALT

T. éch T. PME dp 02 HC CO Avoc FAP upstream REGIME or FAP without additit trtmn CC bar mbar% ppm g / h ppm a / h 1500 498 124 0 705 17.5 46 2.00 265 23.00 with - 1500 189 161 0 892 16.8 410 16.8 660 54.8 with Al = 0 No r ~ ~ n ~ r ~ iG ..
1500 ¦ 170 ¦ 145 ~ ¦ O ¦ 1020`1 17 ¦ 82 ¦ 3.5 ¦ 240 ¦ 20.5 ¦ with sponlaneous regeneration FSSAIS ON nFs SUIFS A ~ IF ~

10 ~ él ~ .G. ~ F ~ 1 ~ nror ~ tion ~ PS ~ -liP ~

The soot is obtained by pyrolysis of fuel oil cG, leading to the additive. A tube says ~ tube reactor is parounu by a gas flow consisting of, .. mixture of nitrogen and oxygen 98/2 (by volume). The reactor tube is heated ~ thanks to an oven and the gas flow is thus 15 raised to 1200C. Upstream of the oven, the fuel oil, with or without additive, is sprayed very finely. The fuel oil droplets are there by the gas flow and are also brought to 1220C.

SUBSTITUTE SHEET (RULE 26 21 ~ 0 1 8 1 Under these conditions the fuel burns partially and forms soot. The soot is then colb ~ 1ées downstream of the pyrolysis furnace by filtration of the flow g ~ e ~ x. If the fuel oil "binds a metallic additive, the metal is found in the form of oxide 5 i, ltin, e ".ellt mixed with soot.

The fuel injection rate upstream of the pyrolysis oven is adjusted to 10 mUh. In these conditions the dia .., at ~ e means of particles elg ", whole soot pro ~ uites by pyrolysis is ideal, linked to that of soot produced by a diesel engine.
According to studies carried out by the plaintiff, the ~ Jd; 1ifs metallic are uti'is ~ s to a conc6llt ~ lioll in the ga_ole motor telb that c ~ e.ltlaliGn in metal in the ~ a_ole be co, - ~ .rise between 0 and 200 ppm. Under these conditions, the conce.lt ~ io. ~ s of metal in the soot produced by a motor powered by a diesel additive are cc,. ". between 0 and 4%.
cGm --- e the final cGIlcelltldtbn in catalyst in b soot is one of the par ~ -, and ~ ds illl ~ Gl ~ which condition the ten, per ~ ture of illn ~ llmaliG-I, we had to search what cG-, cellt ~ dlbn metal in the fuel oil it was necessary to have to obtain the same conc6. It ~ liol, metal in the soot obtained by pyrolysis.
20 We have l - o-lt ~ é that it is necessary ~; re that b concellt ~ dti ~ metal in the fuel is multiplied by 20 by ~ l to b conce-lt ~ i ~) as an additive in diesel fuel.
The interval is thus of the order of 0 to 4000 ppm by mass.
In conclusion, in order for the soot obtained by pyrolysis to be re ~, resentali / engine soot eses, it is necessary to multiply by 20 the conce- I ~ dliOI, as an additive in fuel oil.

The study of the soot ear AnPlyse ll.er.,. O ~ revimétri ~ ue o ~ ATr ~

The soot produced by the pyrolysis oven can be received, erected in ATG.
The horns, Jitio "s are:

Sé ~ r ~,.: Model TG92 35 Flow g ~ s ~ x 2.3Uh Air gas W095 / 18198 2 1 8 0 1 8 1 PCT / FR94tO1560 Temperature increasing from 20 to 900C due to 1 0C / min Mass of soot analyzed 20 mg The ATG e-, r6 ~; ~ e the mass of soot remaining in for ~ tiGn of time. By convention we define the ten ~ p ~ rdture of ildl ~ ill-lldliGn cG """e the ~ scisse of the defined point com "~ e l'i, lt ~. ~ tion of the baseline originally with the tan ~ 6" le at the curve where the comb ~ ~ stion speed is maximum (i.e. at the point of inflection of the 10 curve called in ~ S ~).

Study of r ~ Ar ~ des ~ - ~ ies o ~ e ~ e ~ e ~ r ~ olyse ~ g ~ oles contenp- ~ t ies ~ jtifs C ~ S ~ is Irh I ~ ntllarle. of re-drunk and ~ ie co ~ l ~ -Copper and cobalt are two metals which are known for their cal- ci ~ ed to ~ heisser the te "". er ~ illflalllmdti ture ~, l, are deemed to ~ ues and induce thermal shock .lan ~ 6reux for the filter. One of the objects of the present study was to ", ~, lt ~ er the synergy which exists between a metal cG"", - e copper or cobalt 20 opposite 1 ~ Itl, ~) e.

The soot was all produced; ~ ss by the metl, Gde described below ~ Js and their ~ combustion titude was measured by ATG. Ies conce, lbdti ~ n ~ metal in fuel oil are certainly very ~ l ~ v60s, but they do- ~ l) ellt indicdtions on a 25 implementation on engine bench with concelltldtions in the diesel used as fuel cGrlespG "d ~ t about 1 / 20th of the conceiltldli ~ ns in the fuel oil.

30 ~ tifs used The names of the additives used for this study, and their characteristics are grouped in t ~ ableau 1:

218 ~ 1BI

TA ~ IF ~ U 5 Characteristics dw additives used Name of additive Concentration of metal in The addit in%
Ceka "copper wire 9.2 Cobalt octoate 10 Lanthanum octoate 10.23 The tables below give the t ~ "" ~ gr ~ l ~ Jres ~ lldliGI) of soot in Fon ~ tion of the concen ~ liGn metal in fuel oil.

TA ~ IF ~ l (D6 Ignition temperature as a function of concentration in metal a ~ iss ~ nt alone in fuel oil (examples com, & r ~ ti ~ s) n CONCENTRATION IN METALS TEMPERATURE (in C) TEST IN THE OIL
(mmol / ka) Lanthan Conc. Inflam- Abais-total lanthanum 2 Copper: 3.04 3.04 470 -20 3 Copper: 7.14 7.14 375 -115

4 Copper: 10.7 10.7 370 -120 Copper: 14.2 14.2 360 -130 6 Copper: 17.8 17.8 360 -130 7 Copper: 26.8 26.8 355 -135 8 Copper: 28.5 28.5 355 -135 9 Cobalt: 3.56 3.56 435 -55 Cobalt: 7.12 7.12 375 -115 11 Cobalt: 10.7 10.7 355 -135 12 Cobalt: 14.3 14.3 365 -125 13 Cobalt: 17.8 17.8 335 -155 Ignition temperature as a function of the conc ~ lion lanthanum acting alone in fuel oil n CONCENTRATION TEST IN METALS TEMPERATURE (in C) IN THE tioul (mmoUlcn) lanthanaduvant of the concentration of inflam- abais-lanthanum tration mation total 14 14.3 0 14.3 410 -80 38.9 0 38.9 400 -90 ~ 1 ~ 0181 WO 95 / lX198 PCT / FR94 / 01560 ~ _ 31 T ~ IRI F'IU 8 Inf q temperature "", ~ tion depending on the composition of additives in fuel oil - n CONCENTRATION IN METALS TEMPERATURE (in C) TEST IN THE OIL
(mmollka) L ~ ll.a-, Adjuvant of Conc. Inflam- Abais-total lanthanum 16 7.14 Copper: 3.56 10.7 380 -110 17 7.14 Copper: 7.14 14.3 375 -115 18 7.14 Copper: 10.7 17.8 370 -120 19 10.7 Copper: 3.56 14.3 400 -90 8.53 Copper: 7.14 15.7 360 -130 21 14.3 Copper: 3.56 17.8 380 -110 22 9.03 Copper: 8.83 17.8 370 -120 23 5.40 Copper: 5.28 10.7 405 -85 24 9.00 Copper: 26.8 35.8 340 -150 13.44 Cobalt: 12.18 25.62 360 -130 26 5.62 Cobalt: 5.09 10.71 377 -113 27 4.70 Cobalt: 6.11 10.81 360 -130 28 7.14 Coba ~: 3.56 10.70 395 -95 29 7.14 Cobalt: 7.14 14.28 365 -125 7.14 Cobalt: 10.71 17.85 355 -135 31 10.75 Cobalt: 3.56 14.31 350 -140 32 10.75 Cobalt: 7.14 17.89 360 -130 33 14.28 Cobalt: 3.56 17.84 375 -115

Claims (32)

1) Process for treating soot containing one or more rare earths wherein said soot is brought into contact with a gas containing oxygen, characterized in that said gas has a temperature between 200 and 400°C, and by the fact that the partial pressure in oxygen of said oxygen-containing gas is at least 3%
of atmosphere, i.e. 3.103 Pascals advantageously at 4% of atmosphere, i.e. 4.103 Pascals. 2) Process according to claim 1 characterized in that the contact between the gas containing oxygen and the soot is maintained for a period of sufficient time to burn at least 90% of the soot. 3) Method according to one of claims 1 and 2 characterized in that at least a portion of said oxygen-containing gas originates from air heated to the contact with any part of the engine or its attachments. 4) Method according to one of claims 1 to 3 characterized in that said oxygen-containing gas at least partially contains the gases engine exhaust. 5) Method according to one of claims 1 to 5 characterized in that said engine is an internal combustion engine, preferably an engine diesel. 6) Method according to one of claims 1 to 5 characterized in that the soot is that emitted by an internal combustion engine, preferably diesel, equipped with a "turbo". 7) Method according to one of claims 1 to 6 characterized in that the rare earths are present in the soot at a level between 500 PPMet5%. 8) Method according to one of claims 1 to 7 characterized in that said engine is fitted with a particulate filter. 9) Method according to one of claims 1 to 8 characterized in that the particles contained in the filter are subjected intermittently under the conditions of this process. 10) Process according to claim 1, for treating the soot produced by a internal combustion engine, characterized in that it comprises the provisions following:

introducing into the combustion chamber at least one derivative of rare earths or mixture of rare earths at a concentration of between 10ppm and 500 ppm (by mass), preferably between 20ppm and 200ppm;

collect on a filter the soot produced by the combustion engine internal, the temperature of the gases entering the filter being chosen in the range 100°C-350°C;
and allow the soot to build up until it reaches a steady state or significant fraction of incoming soot is compensated by the combustion of soot in the soot cake on the filter and do not plan any regeneration as long as the loss in charge caused by the soot does not exceed one value chosen in advance and not exceeding 0.5 bar (5.104Pa). 11) Process according to claims 3 to 8, and 10, characterized in that said rare earth is introduced into the engine via air. 12) Process according to claims 3 to 8, and 10, characterized in that said rare earth is introduced into the engine through the fuel. 13) Process according to claim 12, characterized in that the content of rare earths of said fuel is between 50 and 150 ppm. 14) Process according to claim 10 to 13, characterized in that the temperature at which the gases are filtered is between 200 and 350°C. 15) Method according to one of claims 10 to 15, characterized in that said rare earth is cerium or a cerium compound. 16) Method according to one of claims 10 to 16, characterized in that the surface of the filter is chosen so as to maintain the pressure drop in said filter at a value at most equal to 0.3 bar, advantageously to 0.2 bar. 17) Method according to one of claims 10 to 17, characterized in that the temperature of the gases in contact with the filter is chosen so as to maintain the pressure drop in said filter to a value at most equal to 0.3 bar, advantageously at 0.2 bar. 18) Method according to one of claims 10 to 18, characterized in that the rare earth content in the fuel is chosen in such a way as to maintain the pressure drop in said filter at a value at most equal to 0.3 bar, advantageously at 0.2 bar. 19) Process according to claim 1 for reducing the emission of soot from a internal combustion engine through which exhaust gases are passed through a particulate filter, characterized in that an additive is introduced containing lanthanum. 20) A method of treatment according to claim 19, characterized in that the lanthanum is added to the fuel in the form of a salt or a stable sol in said fuel. 21) Process according to claim 21, characterized in that one introduces the lanthanum-containing compound directly into the engine. 22) Method according to one of claims 19 and 22, characterized in that the lanthanum content of the fuel is between 10 and 1000 ppm, advantageously between 20 and 200 ppm, preferably between 50 and 150 ppm. 23) Method according to one of claims 1, 2 and 4, characterized in that the soil and/or the salt are introduced so as to form aggregates of crystallites whose largest dimension is between 20 and 10,000 angstroms (2 and 1000 nm) and whose crystallite size is between 20 and 250 angstroms (2 and 25 nm). 24) Process according to claim, characterized in that the lanthanum is introduced into the engine through the air. 25) Additive for internal combustion engine fuel, characterized by the fact that it includes:

a) a compound of a rare earth whose highest oxidation state is the trivalent state, b) a compound comprising at least one transition element or a other rare earth. 26) Adjuvant according to claim 25, characterized in that the content of said rare earth whose highest oxidation state is the trivalent state, relative to the sum of the metallic elements contained in the adjuvant is at least equal at 50%, preferably at 80%. 27) Soot based on trivalent rare earth, characterized by the fact that they can be obtained by combustion in an internal combustion engine of a fuel containing an adjuvant based on trivalent rare earths (that is to say whose state highest oxidation state is the trivalent state) 28) Soot according to claim 27 characterized in that said adjuvant is an adjuvant according to claims 25 and 26. 29) Soots according to claim 27 and 28 characterized in that they have a particle size such that the d20 is at least equal to 200 .ANG. and that the d80 or at most equal to 1000 .ANG. characterized in that they contain at least least 0.01%, advantageously at least 0.1%, preferably at least 0.5% Pascals crystallite aggregate.23 30. Soot according to claim 28, characterized in that said Error!
Bookmark not set. has a total content of rare earth(s) including between 1000 ppm and 30%, preferably from 5% to 10% (by mass). 31. Soot according to claim 28 and 29, characterized in that the grains of said soot form clusters whose d50 is between 2000 and 5000 .ANG.. 32. Soot according to claim 28 to 30, characterized in that said soil rare trivalent is lanthanum.